Are you going to be dropping the trailer at night? If so, it might be possible to weld up something that fits in the receiver. I figured that a square tube at right angle with a hook to tie off of, and then you could attach to your crossed 4x4's on the other end.
I don't have an pictures, but I hung while out in the field, on a tank recovery vehicle (the name of which escapes me right now). Basically, there was a big arm, and I tied both ends to it and slept away.